Road tolls are increasingly common and, for such road tolls, it is important to be able to identify vehicles without the traffic flow being interrupted too much, in order to be able to charge for the vehicle. Also for automatic traffic monitoring, at barriers to protected areas or more generally for monitored areas, it is important to be able to identify a vehicle. Traditionally, for such identification the registration number is read automatically by image processing. However, such image processing requires a high-quality image in order that an incorrect registration number should not be read off, which complicates such a method. For example, dirt and snow can prevent the correct reading of the registration number.
There is thus a great need for improved identification of vehicles.
When parking vehicles in large public car parks, such as at airports, etc., it is a common problem that the vehicle is stolen while the owner is away.
In many cases it is a long time before the theft is discovered. This can, for example, be the case when a person parks his car in an airport car park before a long stay abroad. In this case, the car is usually not notified as missing until the theft is discovered, that is when the owner returns and finds that the car has been stolen.
There is thus a great need to reduce the risk of the theft of vehicles from public car parks.
Entering and exiting car parks can, for example, be carried out in such a way that the driver obtains a car park ticket at an entrance barrier upon which the time is recorded. Before the vehicle is retrieved, payment for the parking must be made, which is checked by means of the car park ticket at an exit barrier, after which the car is allowed to leave. A disadvantage of this system is that no check is made that it is the same car at the exit as at the entrance. The driver may, for example, have parked an old car in poor condition and obtained a car park ticket, in order later to steal a valuable car and drive it out of the car park using his car park ticket.
Another problem is the theft of vehicles by tailgating, that is a stolen vehicle is driven out closely behind another vehicle that is allowed out through the exit barrier.
In U.S. Pat. No. 5,034,739, this problem is solved by a camera placed at the entrance barrier taking a picture of the vehicle's registration plate and storing the image in a computer. At the exit, a second camera then takes a new picture of the vehicle's registration plate, after which the computer compares the two pictures and checks whether a payment has been made for the parking for this vehicle, after which it is allowed to leave.
U.S. Pat. No. 4,775,571 describes a similar solution, but where in addition a picture of the registration plate is transferred onto a car park ticket both at the entrance and at the exit, with both these tickets having to be handed in at the exit barrier together with the payment in order for the car to be allowed to leave.
A disadvantage of these two previously known systems is that the theft of a vehicle can still be carried out by transferring the registration plate to another more valuable car.
GB 2 273 596 describes a vehicle protection system in which data that identifies both the vehicle and the driver are stored together when entering the car park. When exiting, the identities of both the driver and the vehicle are then checked and compared with the stored information. The vehicle identification is carried out by means of a video camera, among other things for obtaining the registration number. It is mentioned, however, that other characteristics of the vehicle can also be determined, such as the orientation of the screws that hold the registration plate and nuances in the vehicle's color.
BE 1010751 also describes a theft prevention system for a car park, where an image is recorded of the vehicle when entering and the image is analyzed, after which the result of the analysis is transferred onto a car park ticket. When exiting, another image of the vehicle is recorded which is analyzed, after which the result of the analysis is compared with the data on the car park ticket. If the data is the same, the vehicle is allowed to leave.
Both these theft prevention systems make the theft of vehicles by changing the registration plate more difficult. However, they have disadvantages, for example problems can arise if the appearance of the vehicle is not the same when entering and exiting, which can be the case in the event of snow falling. In addition, differences in the general lighting at the entrance and exit can make the identification more difficult. It is a considerable disadvantage if the owner of a vehicle is not able to retrieve his own car from a car park because night has fallen while it has been parked, so that the light is different when the car leaves the car park than it was when the car entered the car park.